Apparatus for cleaning a root canal system

ABSTRACT

An endodontic tool is provided to facilitate the removal of the smear layer and to enhance deep lateral cleaning of a root canal system. The tool is comprised of a sonic or ultrasonically driven activator which is made from a strong, flexible, non-metallic, and non-cutting material. The activator can be smooth. A snap-on coupler is adapted to attach the tool to a driver via a snap on action and without the use of tools. The driver will vibrate, sonically or ultrasonically, the flexible activator within a root canal of a tooth. The tool can be provided with fluid passages which allow for irrigating reagents to be delivered through the activator and into the root canal space during endodontic procedures.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending application Ser. No.11/227,934 filed Sep. 15, 2005, now U.S. Pat. No. 8,235,719, which inturn is a continuation-in-part of application Ser. No. 11/104,678 filedApr. 13, 2005, now abandoned, both of which are entitled “Apparatus ForCleaning A Root Canal System” and both of which are incorporated hereinby reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

BACKGROUND OF THE INVENTION

This invention relates to endodontic tools, and in particular, to toolsused during and after an endodontic root canal preparation procedure, tomore effectively clean the root canal system prior to obturation.

Following tooth maturation, the dental pulp is harbored within thestructural elements of the tooth. Frequently, and for a variety ofreasons, the pulp is irreversibly injured, resulting in inflammatory andinfectious conditions which often adversely affect the tooth, itssupporting structures, and the patient's health. Clinically, as analternative to extraction, root canal treatment is performed and ideallydirected towards the elimination of pulp, bacteria, and relatedirritants from the root canal system, followed by three-dimensionallyfilling the root canal space with an inert, biocompatible, dimensionallystable, filling material, such as gutta percha. Ideally, the obturationprocedures will fill not just the main canal, but the fins, webs,cul-de-sacs, lateral canals, and all portals of exit between the rootcanal system and the tooth's attachment apparatus.

Root canal procedures are common. Central to a successful endodontictreatment has been the use of chemical reagents during mechanical rootcanal shaping procedures to completely clean all aspects of the rootcanal system. The chemicals used to enhance canal debridement anddisinfection during cleaning and shaping procedures potentially reachall aspects of the root canal system. The most popular chemicalscurrently used during canal preparation to actively assist in cleaningand disinfecting include bleach, hydrogen peroxide, and chelatingagents. Often, a 2%-5% solution of a clear, pale, greenish-yellowstrongly alkaline solution of sodium hypochlorite (NaOCl) andethylenediaminetetracetic acid (EDTA) are used.

During canal preparation, a solution of NaOCl is liberally irrigatedinto the root canal space where its solvent action facilitates thedigestion and removal of pulp, bacteria, viruses, spores, endotoxins andother irritants generated by the microorganisms. This solution has thepotential to circulate, penetrate and, hence, clean into all aspects ofthe root canal space. However, studies have shown that even the mostthorough use of sodium hypochlorite does not remove all the materialfrom the root canal. The walls of a root canal are comprised of dentin,which contains millions of dentinal tubules per square millimeter.Instruments used to negotiate and shape a canal cut dentin and dentin,in combination with organic substrates, forms dentinal mud. Dentine mud,pulp, bacteria, and other related irritants have been consistentlyvisualized histologically after cleaning and shaping procedures in thedentinal tubules and various aspects of the root canal systems. Thus,after cleaning and shaping procedures, the root canal is still coveredwith a film of debris, frequently described in the literature as a“smear layer.” This “smear layer” includes dentinal mud and/or organicdebris, including the irritants noted above.

After cleaning and shaping, the root canal has been traditionally filledwith gutta percha and a root sealer. However, if the smear layer or filmis not adequately removed from the root canal, the smear layer cancompromise the filling and sealing of the root canal system. Ifobturation is incomplete then the root canal space is predisposed tobacterial leakage and failure. Post-treatment failures attributable toleakage are common and require endodontic retreatment of the tooth orextraction. Thus, for a complete and thorough cleaning, this smear layeror film should be removed. To address the smear layer, practitioners usea weak acid or surfactant, such as 17% EDTA, in an effort to remove thesmear layer. Typically, the root canal is flushed with EDTA, or othersimilar reagents, to accomplish this. Traditionally, some practitionershave used a metal root canal file or a cannula to activate the solutionand enhance the performance of the EDTA. These devices may be usedmanually or mounted in an ultrasonic handpiece to produce vibrations andfluid movement. As an example, even when a file is used, it isimpossible to ensure that the file is brought into contact with thecomplete surface of the root canal, and hence it is difficult to ensurethat substantially all of the smear layer has been removed. Regrettably,the use of ultrasonically driven metal instruments has frequently led toiatrogenic events, such as broken instruments, ledges in the wall of theroot canal preparation, or even perforation of the root canal.

In my prior patent, U.S. Pat. No. 6,179,617, which is incorporatedherein by reference, I disclosed an endodontic brush for use in removingthe smear layer. The brush is comprised of a handle, a shank and a brushsection extending from the shank. The brush section includes a pluralityof bristles extending from a twisted wire core. While this brush worksacceptably, it still has many shortcomings which are due to the factthat the core and shank are disclosed to be made from wire. The twotwisted wires which form the core and shank are each 0.2 mm in diameter,and hence, the core and shank have a diameter of at least 0.4 mm. Whilethe wires are quite thin, even without bristles, the device, at times,has a diameter that is too large to reach the end of many canals. From atechnical standpoint, the wires cannot be made much thinner because thebrush would then become predisposed to breakage during use. Even at thecurrent diameter, the wire shank and core are too flexible. Because ofits high flexibility, an endodontist cannot effectively and purposelybrush the sides of the root canal wall, using a brushing manner, andhence cannot thoroughly remove the smear layer from the root canalpreparation. Additionally, because of the twisted wire core, the brushcannot be driven ultrasonically. The twisted wire core prevents theoptimal transfer of ultrasonic energy to the bristles of the brush.

Since the brush is too large for well-prepared, yet smaller diametercanals, I have found that when the brush is placed into the canal, theirrigant in the canal is partially displaced by the brush. This isundesirable as it is the irrigant that dissolves the smear layer.Whether the brush, disclosed in my above noted patent, or a file, isused to clean a prepared canal, the addition of fresh irrigant requiresthat either tool be removed from the canal to allow for fresh irrigantto be introduced into the canal.

Additionally, prior sonic or ultrasonically driven endodontic toolsrequire that the tool be attached to a driver by means of wrenches. Thismakes it difficult (and sometimes time consuming) to change tools duringa procedure. It would be desirable to make it easier to attach the toolsto, and remove then from, their drivers.

BRIEF SUMMARY OF THE INVENTION

Briefly stated, an endodontic tool or activator is provided tofacilitate the removal of the smear layer and organic debris from theroot canal system after an access cavity to the root canal has beenformed, the root canal orifices have been exposed, and the canals shapedto substantially remove organic materials from the root canal. The toolcomprises a cup-shaped guard, a snap-on coupler, and an activatorextending from the coupler. The activator includes a connecting portionand a flexible, activating portion. The coupler is adapted to snap on toa sonic driver or thread onto an ultrasonic driver to be connectedthereto. By enabling the tool to be snapped onto a driver, the tool canbe connected to its driver without the use of tools (such as wrenches),as is required by the threaded connection. The tool can also be adaptedto be connected to the driver by other means, such as a latch-typeconnection, a frictional connection, a chuck grip connection, etc.

The activator is made from a flexible, non-metallic, non-cuttingmaterial. The activator can, for example, be made from plastic, nylon,or an aromatic polyamide (such as Kevlar®). The activator can begenerally straight (for connection to a contra-angled handpiece) or itcan be contra-angled (for connection to a straight handpiece). Theactivating portion can be substantially parallel (i.e., generallycylindrical) or tapered in design. The activating portion surface can besmooth. The activating portion is narrow at its apical or distal end andcan have diameters as small as about 0.1 mm to about 0.2 mm at itsapical or distal end. At its largest diameter, the apical end of theactivating portion can have a diameter of about 1 mm. Of criticalimportance, this size allows for the tip of the activating portion toreach to the end of a prepared root canal. The activating portion, iftapered, has a taper of between about 0.01 mm/mm and about 0.12 mm/mm.

In one variation of the activator, a lumen extends through at least apart of the overall length of the activator. The activator can beprovided with one or more pores along its lateral surfaces extendingfrom the lumen to the external surface of the device. Preferably, thepores are formed in the activating portion only of the activator. Ifthere are a plurality of pores, then the pores can have a diametersubstantially smaller than the diameter of the lumen. Thus, for example,the pores can have a diameter of about 0.001 mm to about 0.2 mm and thelumen can have a diameter of about 0.1 mm to about 0.5 mm, depending onthe overall size of the tool. The lumen extends through the activator,the entrance to the lumen being at the more proximal end of the tool. Inone variation, the pores do not extend to the very distal end of theactivating portion. Thus, for example, the activating portion could befree of pores between, for example, D₀ and D₁. In another variation, theactivating portion can be provided with pores which extend over the fulllength of the activation portion. In this variation, the pores at thedistal end of the activating portion (i.e., the pores from D₀ to, forexample, D₁) can have a diameter smaller than the remaining pores in theactivating portion.

In use, the method of cleaning a root canal system using the tool of thepresent invention comprises (1) preparing an access cavity in thepatient's tooth; (2) exposing the orifice(s) of the root canal systemwithin the pulp chamber of the tooth; (3) mechanically preparing thecanal to facilitate chemically flushing and removing organic substratesfrom the root canal; (4) repeatedly irrigating and flushing theexpanding preparation during shaping procedures to remove the smearlayer from the internal walls of the shaped canal; (5) repeatedlyirrigating and flushing to encourage the circulation and deep lateralpenetration of the chemical reagent into all aspects of the root canalsystem; (6) agitating the chemical reagents in the root canal systemwith a sonically or ultrasonically driven activator, which has a strong,highly flexible and tapered design made from a non-metallic, non-cuttingmaterial. When the activator is provided with an internal lumen andlateral pores, the method additionally includes passing fresh intracanalirrigating reagents through the lumen and side pores while agitating thetip within the root canal.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is an elevational view of an illustrative embodiment of anendodontic tool of the present invention with a coupler portion of thetool being shown in cross-section;

FIG. 1A is a side elevational view of the endodontic tool mounted to asonic driver.

FIG. 2 is a cross-sectional view of an proximal end of the device,showing the guard and the connector which enables the device to beconnected to a driver;

FIG. 3 is an enlarged fragmentary elevational view of a secondillustrative embodiment of the endodontic tool;

FIG. 4 is an enlarged cross-sectional view taken along line 4-4 of FIG.3;

FIG. 5 is an enlarged cross-sectional view of a variation of the tool ofFIGS. 3 and 4; and

FIG. 6 is a side elevational view of the activator formed as acontra-angled tool.

Corresponding reference numerals will be used throughout the severalfigures of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description illustrates the invention by way ofexample and not by way of limitation. This description will clearlyenable one skilled in the art to make and use the invention, anddescribes several embodiments, adaptations, variations, alternatives anduses of the invention, including what is presently believed to be thebest mode of carrying out the invention. Additionally, it is to beunderstood that the invention is not limited in its application to thedetails of construction and the arrangements of components set forth inthe following description or illustrated in the drawings. The inventionis capable of other embodiments and of being practiced or being carriedout in various ways. Also, it is to be understood that the phraseologyand terminology used herein is for the purpose of description and shouldnot be regarded as limiting.

An illustrative endodontic tool 10 made in accordance with one aspect ofthe present invention includes a hollow guard 12 at the proximal endthereof, a snap-on coupler 14 below the guard 12 and an activator 16extending from the coupler 14. As will be described more fully below,the activator 16 is sized to be received in the root canal of a toothduring and after a root canal preparation procedure, and to extend tothe full length of the root canal.

As seen in FIG. 2, the hollow guard 12 is essentially cup-shaped and hasan opening 18 at the bottom thereof. The opening 18 leads into theconnector 14. The guard 12 and coupler 14 are sized and shaped toreceive the end of a sonic driver D which will vibrationally drive theactivator 16. The driver can, for example, be a driver as shown anddescribed in our U.S. Pat. No. 7,261,561, entitled “Vibrational DriverFor Endodontic Activators” and which is incorporated herein byreference. The cup-shaped guard forms a shield about the driver duringuse to reduce the amount of fluids or aerosols that will spray againstthe driver during use.

The coupler 14 is adapted to removably engage the end of the driver. Asshown in FIGS. 1 and 2, the coupler 14 includes a recess 20 which canreceive a projection on the tip of the driver. The recess 20 cancomprise one or more discrete holes, depressions, notches, etc. spacedabout the inner circumference of the coupler (as shown in the figures)or a continuous circumferential groove. Alternatively, the recess 20could be replaced with a rib or series of discrete projections or evenspring mounted pins or balls, which would then be received in a grooveor series of notches/indentations in the driver tip.

The activator 16 comprises two portions, an activating portion 22 and aconnecting portion 24. The activating portion 22 has a length of about16 mm, and has a diameter D₀ at the distal tip thereof and a diameterD₁₆ at the upper end of the activating portion 22. The activatingportion 22 can have generally straight sides but is preferably tapered.The activating portion can be cylindrical, square, rectangular,triangular, or paddle shaped; and each of these shapes can then beeither generally straight or tapered. The activating portion 22 has adistal tip diameter D₀ of between about 0.1 mm or 0.2 mm and up to about1.5 mm, and a proximal diameter D₁₆ of between about 1 mm and 2 mm atits most proximal end. The taper of the activating portion can bebetween about 0.01 mm/mm and about 0.12 mm/mm (i.e., between about 1%and about 12%).

The connecting portion 24 has a length of between about 2 mm and about15 mm, such that the overall length of the activator 16 is between about18 mm and about 31 mm. The activator connecting portion 24 can begenerally cylindrical. Alternatively, the connecting portion 24 cancontinue the taper of the activating portion 22.

The tool 10 can be made available in multiple sizes, such as small,medium, and large, to cover variations in the diameter of fully shapedcanals following root canal preparation procedures. Additionally, theoverall length of the activators can vary to address the variations inthe working lengths of teeth. For example, the activators can be about18, 21, and up to 31 mm in overall length. Thus, for example, the smalltool can have a D₀ tip diameter of about 0.1 or 0.2 mm and a D₁₆diameter of about 0.52 mm; the medium tool can have a D₀ tip diameter ofabout 0.3 mm and a D₁₆ diameter of about 0.94 mm; the large tool canhave a D₀ tip diameter of about 0.5 mm and a D₁₆ diameter of about 1.5mm. These are examples of three possible dimension combinations. Ofcourse, the diameters of the activating portion 22 can vary toaccommodate different sized root canals. Thus, the D₀ diameter can be aslarge as 1.5 mm and the D₁₆ diameter can be as larger as 2 mm. Theconnecting portion of the activator from D₁₆ to the bottom of thecoupler 14 as noted above, can either continue to taper or be generallycylindrical. The activator 16 can be permanently fixed to the snap-oncoupler 14, which in turn is attached to the guard 12. The three toolseach have different diameters and tapers and are provided as a set. Eachtool comprises a proximal guard 12, a snap-on coupler 14, and a distalactivator 16. The tool 10 can then be used as needed, as will bedescribed further below.

The activator 16 is formed from a strong, highly flexible, smooth,non-metallic and non-cutting material. The activator 16 is shown in FIG.1 in a bent or curved position. This is to show some of the flexibilityof the activator 16. In fact, that activator 16 is sufficiently flexibleto be bent into a U-shape. The tool 10 can be made from a variety ofmaterials such as plastic, nylon, or an aromatic polyamide containingelastomers, such as are available from E. I. du Pont de Nemours andCompany under the name Kevlar®. Nylon, for example, can be manufacturedwith different D₀ diameters and tapers to provide a strong, highlyflexible activating portion 22 that can safely pass through canals thatexhibit multiplanar curvatures.

The activating portion 22 has a smooth surface. However, if desired, thesurface of the activating portion can be flocked and/or textured.

The tool 10, as noted above, is adapted at its proximal end to receive amale driver which extends through the guard 12 and into the coupler 14.The driver includes a sonic or ultrasonic generator. Such a driver canuse piezoelectric or magnetostrictive elements, for example. In ourwork, we have found that a Water Pik® driver, commercially availablefrom Water Pik, Inc. of Newport Beach, Calif., works well as a sonicdriver for the activator 16. A preferred driver for sonic applicationsis the driver described in our above noted U.S. Pat. No. 7,261,561,entitled “Vibrational Driver For Endodontic Activators” and which isincorporated herein by reference.

When the activating portion 22 is inserted into a fluid-filled andshaped root canal, and its driver activated, the sonic energy of thedriver will, due to the shape of the activating portion 22, cause theflexible most distal tip of the activating portion 22 to vibrate in thefluid in the root canal, which is termed cavitation; vigorous movementof fluids lateral to the activating portion 22 is termed acousticstreaming. If the driver is a sonic driver, the activating portion 22can vibrate between about 1 KHz to 10 KHz; if the driver is amagnetostrictive generator, the activating portion will vibrate at about15-24 kHz; and if the driver is a piezoelectric ultrasonic generator,the activating portion 22 will vibrate at about 22 Khz to 40 KHz.Because the activating portion 22 is very strong and flexible, thevibrations induced in the activating portion 22 by the driver will causecavitation and acoustic streaming of the solution within the root canal.This phenomenon will dislodge and remove the smear layer from theprepared walls of the canal and, further, serve to provide a techniquefor deep lateral cleaning into all aspects of the root canal system. Tomaximize cavitation and acoustic streaming, the canal must be filledwith irrigating solutions, such as sodium hypochlorite, EDTA asdiscussed above, or other final rinse solutions. The activating portion22 of the tool 10 is shaped such that when the tool is activated withina root canal filled with the irrigating solution, the vibrations of themore distal tip within the root canal will cause the irrigating solutionto cavitate. Agitating the intracanal irrigant lateral to the activatorwill initiate acoustic streaming; together, cavitation and acousticstreaming cause the intracanal irrigating solution to become turbulent,facilitating the removal of the smear layer and promoting deep lateralcleaning within the root canal system.

Stated differently, by driving the flexible, non-cutting, andnon-metallic activator 16, even at only sonic speeds, the turbulenceinduced to the irrigating solution by the vibrating activator willenhance the effectiveness of the irrigating solution by bringing more ofthe solution into contact with the walls of the root canal and into theinaccessible areas of the root canal system. Additionally, as theactivator 16 vibrates within the root canal, its lateral walls willcontact and rub against the surfaces of the root canal to physicallyenhance the chemical action of the irrigating solution. This action willresult in a better removal of the smear layer within the root canal thancan be accomplished with, for example, files. Further, because theactivator is made from a non-metallic and non-cutting material, as notedabove, the physical action of the tool within the root canal will notdamage the internal walls of the canal. Specifically, the use of theactivator 16 will not result in apical transportation or ledge formationwithin the canal, which can occur when using stiffer devices, such asmetal files or cannuli. Further, this method of cleaning will reduce thepossibility of other iatrogenic events.

In another embodiment, the tool (FIGS. 3-4) can be provided with aninternal lumen or flow path 30, which extends through the activatingportion 22′ and at least a part of the connector portion (not shown inFIG. 3 or 4) of the tool. The lumen 30 does not extend to the mostdistal end or tip of the activating portion 22, but rather ends short ofthe distal end, as seen in FIG. 4. This lateral design feature safelyconfines the irrigant to the root canal. A plurality of small openingsor pores 32 extend from the lateral surfaces 34 of the activatingportion 22 to the lumen 30. The pores 32 are shown to extend generallyradially, but could extend from the lumen 30 at some other desiredangle. The pores are located only in the activating portion 22 of theactivator 16′, and thus are formed only between the diameters D₀ and D₁₆of the activator 16′. The connecting portion 24 (which generally willnot extend into a tooth) will be free of pores.

The size of the lumen 30 and the pores 32 is determined in part by thesize of the activator 16. The lumen 30 can have a diameter of betweenabout 0.1 mm and about 0.5 mm. The pores 32 have a diameter smaller thanthe diameter of the lumen 30. The pore diameter can be between 0.001 mmand about 0.2 mm.

The pores 32, as seen in FIGS. 3 and 4, do not extend to the very distalend of the activating portion 22. Rather, they end short of the verydistal end. For example, the pores can be absent from the region betweenD₀ and D₁.

However, as seen in FIG. 5, pores 35 can be formed to extend from theend of the lumen 30 to the activator surface between D₀ and D₁ (i.e.,the area which is void of pores 32). The pores 35 can be the same sizeas the pores 32, or can be smaller than the pores 32. For example, thepores 35 can be as small as 0.001 mm (1 micron).

The activator 16′ is shown to have a plurality of pores which exitlaterally from the side of the activator or near the bottom of theactivator. The activator could, instead, be provided with a single porewhich exits either along the side or lateral of surface 34 of theactivator or proximate the apical end of the activator. If the poreexits from the side or lateral surface of the activator, the fluid flowpath defined by the lumen 30 and the exit pore would generally beL-shaped. It will be appreciated that such an L-shaped flow path coulddefine an angle of less than 90°, or otherwise have a curvature tofacilitate the flow of fluid through the flow path and to reducepressure losses in the fluid stream due to bends in the flow path. Ifthe pore exits just proximal to the distal end of the activator, thefluid flow path can be generally straight or have a slight curvaturenear the bottom. Because there is only a single pore or exit opening,the exit can have a diameter that is generally equal to the diameter ofthe lumen 30. Alternatively, this single exit pore could have adiameter, as described above, which is smaller than the diameter of thelumen 30.

As noted above, the lumen 30 extends at least through a part of theactivator connecting portion 24, to enable the activator 16 to beconnected to a source of irrigant, and into the activating portion asdescribed above. In one embodiment, the lumen 30 can extend through theactivating portion 22 and the connecting portion 24 to open into thecoupler 14. The snap-on coupler 14 of the tool, in turn, is constructedto be connected to a source of irrigant, which can be associated withthe driver. To provide for a fluid tight seal between the coupler 14 andthe driver, a groove 36 (FIG. 2) can be provided to receive an O-ring.Alternatively, the O-ring or other seal can be provided on the driver.The O-ring will form a liquid-tight seal between the tool connector andthe liquid output from the drive. Thus, in addition to sonically orultrasonically vibrating the activator 16′, the driver will also deliverirrigant through the lumen 30 and out through the pores 32 (and pores 36if provided). In general, the irrigant will exit along the lateral sidesof the activating portion 22′, or depending on the construction of theactivator, the irrigant may exit as a mist through the smaller pores 36extending from the lumen 30 to the most distal aspect of the activatingportion. Thus, during the irrigating procedure, as described above, theroot canal will be supplied with fresh irrigant during the irrigatingprocess to replace used irrigant. When energized by the driver, theactivating portion 22 of the tool 10 produces cavitation and acousticstreaming, which are optimized in a canal filled with fresh irrigant.

A further embodiment of the activator is shown in FIG. 6. The activator10″, as can be seen, is a contra-angled activator. The activators 10 and10′ on the other hand are “straight” activators. The straight activators10 and 10′ are designed to be received on a contra-angled handpiece. Theactivator 10″, on the other hand, is designed to be received on astraight ultrasonic handpiece, such as is commercially available fromSybronEndo, Obtura Spartan, Tulsa Dental, etc. The structure andfunction of such handpieces are well known to those skilled in the artand will not be described or shown herein.

The activator 10″ includes a coupler 14″ which is configured, as knownin the art, to enable the activator 10″ to be mounted to a commerciallyavailable straight, ultrasonic handpiece, as just described. Thus, thecoupler 14″ will have a threaded bore which allows the activator 10″ tobe threaded onto an end of the handpiece. Additionally, the couplerincludes at least some flat faces to enable the activator to betightened down on the handpiece by the use of a wrench or other tool. Anactivator 16″ extends from the coupler 14″ and comprises a connectingportion 24″ which extends from the coupler 14″ and an activator portion22″ which extends from the connecting potion. The activator 16″ isshaped, as seen in FIG. 6, to form a contra-angle. To this end, theconnecting portion 24″ includes a portion 24 a and a second portion 24b. The first portion 24 a is generally co-axial with, and extendsgenerally straight from, the end of the coupler 14″. The second portion24 b is angled upwardly relative to portion 24 a, with respect to thedrawing of FIG. 6. The angle between portions 24 b and 24 a can definean angle α of about 85°. The activator portion 22″ then extendsforwardly and downwardly from the end of the connecting portion 24 b,and forms an angle β therewith of about 90°. The size of the anglesdefined by the activator 16″ can vary, as is known to those skilled inthe art. As with the tools 10 or 10′, at least the activator 16″ is madefrom a non-metal, non-cutting material, as described above in connectionwith the tool 10. The coupler 14″ is preferably made from the samematerial as the activator 16″, but can be made from a differentmaterial, if desired. The activator 16″ can be solid, as is theactivator 16, or can be provided with one or more pores, in the samemanner as the activator 16′.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense. Although the activator is shown and described to be adapted to besnapped or threaded onto a driver, the activator can be adapted to beconnected or attached to the driver in other ways. For example, theactivator can be adapted to be attached to the driver via a latch-typeconnection, a friction grip connection, a chuck-type connection, or anyother type of connection which will enable the driver to inducevibrations in the activator portion of the activator tool. The activatorportion (22, 22′, 22″) is shown to be circular in cross-section andtapered over its length. As noted above, the activator portion can begenerally straight (rather than tapered) and can be provided with othercross-sectional shapes, as may be desired. These examples are merelyillustrative.

1. A tool for activating intracanal irrigants during an endodonticprocedure, the tool comprising: a coupler having an upper surface and alower surface; said coupler defining an upwardly opening cavity whichextends into said coupler from said upper surface; said cavity beingsized, shaped and configured to removably and snappingly engage a drivenmember of a sonic driver to which the tool is connected when in use; ashield comprised of a surface the entirety of which extends upwardly andoutwardly from said upper surface of said coupler; said shield having abottom defining a junction with said coupler and a top; said bottom ofsaid shield surrounding said upwardly opening cavity; said top of saidshield defining a distal end of said tool; and a flexible activatorextending distally from the lower surface of the coupler; the activatorcomprising an elongate activating portion having an elongate side wall;said activator portion having a length such that the activator portioncan extend to an end of a prepared canal of a tooth and a diametersufficiently smaller than the diameter of the prepared root canal suchthat a most distal tip of the activation portion can vibrate in solutionin the root canal when activated; the activating portion being made froma flexible, non-cutting material having a hardness less than thehardness of a root canal wall such that the will not damage the walls ofthe canal during use of the tool; the activator a being shaped totransmit sonic vibrations to said activating portion of the activatorwhen sonically vibrated; said activating portion being shaped, such thatwhen it is sonically vibrated it will agitate fluid in a fluid-filledroot canal of a tooth to enhance deep lateral cleaning of the root canalsystem of the tooth.
 2. The tool of claim 1 wherein the activatingportion is made from a non-metallic material.
 3. The tool of claim 1wherein the activator is made from plastic, nylon, or aromaticpolyamide.
 4. The tool of claim 1 wherein the activating portion has asmooth axial outer surface.
 5. The tool of claim 1 wherein said cavitydefines a groove to receive an O-ring to form a seal between saidvibrated member of said driver and said coupler.
 6. The tool of claim 1wherein the shield is cup-shaped.
 7. The tool of claim 1 wherein theactivator is contra angled.
 8. The tool of claim 1 wherein the activatorincludes a connecting portion extending between the coupler and theactivating portion.
 9. The tool of claim 1 wherein the tool furthercomprises a flow path, said flow path comprising a lumen which extendsthrough at least a part the activator and an exit opening on a surfaceof the activator.
 10. The tool of claim 9 wherein said lumencommunicates with the coupler.
 11. The tool of claim 9 wherein said exitopening is sized such that fluid exits the activator portion through theexit opening as a mist.
 12. The tool of claim 9 wherein the exit openingcomprises a plurality of pores, said pores being formed only on theactivating portion of the activator.
 13. The tool of claim 12 whereinthe activating portion is free of pores at a distal end of theactivating portion.
 14. The tool of claim 12 wherein the pores have adiameter smaller than the diameter of the lumen.
 15. The tool of claim14 wherein the pores have a diameter of about 0.001 mm to about 0.2 mmand the lumen has a diameter of about 0.10 mm to about 0.5 mm.
 16. Thetool of claim 14 including pores at the distal end of the activatingportion.
 17. The tool of claim 16 wherein the pores at the distal end ofthe activating portion are smaller than pores above the distal end ofthe activating portion.
 18. The tool of claim 17 wherein the pores atthe distal end of the activating portion are between 0.001 mm and 0.01mm in diameter.
 19. The tool of claim 1 wherein the activating portionhas a D₀ diameter, at a most distal end of about 0.1 to about 0.2 mm.20. The tool of claim 1 wherein the activating portion is tapered alongits length, the taper of the activating portion being between about 0.01mm/mm and about 0.12 mm/mm.